Internal-combustion engine



Aug. 27, 1929. D. J. STEBBINS INTERNAL COMBUSTION ENGINE Filed June 1926 INVENTOR 0. J. Srsaauvs BY ATTORNEYS Patented Aug. 27, 1929.

UNITED STATES DWIGHT JONAS STEBBINS, OF MORRIS, MINNESOTA.

INTERNAL-COMBUSTION ENGINE.

Application filed .Tune 26,

My invention relates to improvements in internal combustion engines, and it consists in the combinations, constructions, and arrangements herein described and claimed.

An object of my invention is to provide a novel form of two-cycle engine in which the scavenging of the cylinders is more effectually accomplished than in the twocyclc engine of the ordinary type, thereby giving more complete combustion and resulting in a gain in power and fuel economy.

A further object of my invention is to provide an internal combustion engine of relatively light weight as compared with the power generated.

11 further object of my invention is to provide an engine having fewer parts and being therefore cheaper to build than the ordinary internal combustion engine of the four-cycle type.

A further object of my invention is to provide a device in which any gasoline which may have worked past the piston is returned to the carburetor, thus resulting in a saving in fuel and obviating any danger of the dilution of the oil in the crank case.

A further object of my invention is to provide an engine in which the stroke of the piston is cushioned, and in which the operation therefore is smooth.

Ether objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claim.

My invention is illustrated in the accom panying drawings, forming part of this application, in which Figure 1 is a sectional view of a portion of an engine constructed according to my invention,

Figure 2 is a side view of a cylinder block,

Figures 3 and i are diagrammatical views, showing the operation of the engine, and

Figure 5 is a diagrammatical View of a modified form of the device.

In carrying out my invention, I make use of a cylinder block 1 of the usual type. In the present instance, see Figure 2, I have shown a block of four cylinders, although it is obvious that a greater or a lesser number might be used without departing from the spirit of the invention. One of these cylinders 2 is shown in Figure 1. It is provided with the usual water jacket 3,

1926. Serial No. 118,800.

and, in the present instance, is shown as having overhead valves. Any suitable means for operating these valves may be employed. In Figure 1, I have shown a cam shaft 4 as operating a push rod 5 which in turn actuates a rocker arm 6 which engages the stem of a valve 7. This valve is similar to the other valves used in connection with the device, certain of these valvesbeing intake valves and the others exhaust valves.

One of the features of the presentinvention is to admit the fuel and the air with which it is mixed under pressure into the cylinders. This air pressure may be effected by an exterior compressor. In the present instance, however, I have shown a construction in which the engine cylinder and the engine piston form the air compressing means. To this end, the lower part of the cylinder 2 is provided with an air inlet valve 8, see Figures 3 and 4t, and with an outlet valve 9. These valves are designed to be operated mechanically byany suitable mechanism. In Figure 1, I have shown such mechanism as consisting of a rocker arm 10 having a roller 11 arranged to be engaged by a cam on the cam shaft 4, this rocker arm in turn operating the valve 8 in a manner similar to that described in connection with the valve 7 The valves 9 are operated in the same manner.

The piston 12 has a piston rod 13 which is preferably connected with a crosshead lt in crosshead guides 15 secured to the cylinder block. supported in any suitable way, as by laterally extending supports 16. The crosshead is connected by a pitman 17 to the crank shaft 18. In Figure 2, I have shown a carburetor 19. This carburetor is connected by laterally extending pipes 20 with the intake ports, such as that shown at 21 in Figure 1. At the bottom of each cylinder is a'pipe 22 which is controlled by the valve 9, see Figures 1, 3 and 4. These pipes connect with a manifold 23, which in turn leads to a pipe 24, and thence into the carburetor 19, so as to deliver air from the cylinder 2 to the carburetor. The fuel supply pipe 25 leads to a needle valve 26 by means of which the fuel under pressure may be sprayed into the air in the mixing chamber of the carburetor, which is delivered through the pipe 24. The fuel may be put under pressure These guides may be further '7 by any suitable means, not shown, and is of course preferably under greater pressure than the air.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. Let us assume that the piston 12 is at the top of the cylinder 2 and is starting downwardly on the intake stroke. The intake valve, such as that shown at 7, is opened to permit the entrance of the air and fuel under pressure. The oiston now descends to approximately onefth of the stroke, and the intake valve at this moment is closed by the valve operating mechanism. The explosive mixture, being under compression, is ignited by the spark from a spark plug 40, and the piston is driven forwardly. In Figure 1, the piston would be driven downwardly. The valve 9, see Figures 3 and 4, does not open immediately on the first downward stroke of the piston, but after the piston has taken three-fourths or four-fifths of its travel downwardly, the valve 9 is opened mechanically and the air in the cylinder 2 is forced through the pipe 22, the manifold 23 and the pipe 24 into the carburetor.

On the up stroke of the piston, the eX- haustvalve 28 is opened as is also the air inlet valve 8 at the bottom of the cylinder 2. The upward movement of the piston drives out the exhaust gases or products of coinbustion from the interior of the cylinder, and this results in a very complete and effectual scavenging of the cylinder. On the next downward stroke, the operations are repeated. The valve 8 of course closes, so that the air underneath the piston is compressed, as stated, to a point which enables it to prevent the rush of'air backwardly from the pipes 24 and 23 in which there is pressure from the previous strokes of the piston.

It will be seen that with this arrangement, there will be twice as many power strokes as in a four-cycle engine. Furthermore, withthis construction, there is liability of burned gases rqnaining in the cylinder. In stead, the products of combustion are completely forced out of the cylinder, so that the explosive charge is virtually a mixture of fuel and pure air under pressure. This of course gives more power.

In the ordinary four-cycle engine, as well as in the ordinary two-cycle engine, there is no cushioning 'efl'ect at the end of the power stroke. In the present lnstance, however, there is a cushioning efi'ect, due to the compression of the air underneath the piston. This tends to render the action of the engine more smooth than the ordinary type of engine, in which there is no such cushioning effect.

Another feature to which I desire to call attention is the fact that in this arrange ment, the application of the power stroke is not at all near dead center as in the ordinary type, but occurs when the pitson has descended for a certain distance, as stated, so that there is a greater component of force exerted at the beginning of the working or explosion stroke, and less toward the crank shaft, thereby resulting in less wear on the crank shaft and more effectual power in turning the latter.

In Figure 5, I have shown a modified form of the device which may be used with an ordinary carburetor, that is to say, with the carburetor having a float valve where the fuel is not under pressure in the carburetor. In this instance, the carburetor 29 is connected to the bottom of the cylinder 2 and the air may enter at 30 to mix with the fuel entering the pipe 31. As the piston 12 ascends, the fuel is drawn into the chamber underneath the piston, and when the piston descends, it is compressed and then is forced past the valve 9, which is actuated to permit it to enter the pipe 32, and from whence it is delivered to the manifold 83. and thence by the pipe 84 to the intake, such as that shown. at 21 in Figure 1. In both cases, however, it will he observed that the mixture of fuel and air is'compressed so as to enter the cylinder under compression.

I claim:

In an internal combustion engine, a cylin der, a piston disposed in said cylinder and arranged for travel substantially the entire length of the cylinder, an intake, an intake valve opening into the cylinder at one end thereof for controlling the admission of an explosive mixture into the cylinder from said intake, an exhaust valve at the same end of the cylinder as the intake valve, an air inlet and an air exhaust valve at the opposite end of the cylinder, a carburetor positioned substantially midway between said intake valve and said air exhaust valve. means for connecting the air exhaust with the carburetor, means for connecting the carburetor with said intake, and means for positively actuating all of said valves.

DWIGHT JONAS STEBBINS. 

